The anti-communists strongly criticized Marxist theories during the conference.

anti-communists 是由前缀 anti-（表示"反对"）和名词 communists（共产主义者）组成的复合名词。anti- 是常见的否定前缀，communists 指信仰共产主义的人。 anti-communists 指"反对共产主义的人"，即"反共分子"或"反共人士"。